The hydrogenation of diene-containing polymers, such as butadiene-styrene copolymers and the like, yield substances of greater saturation and, consequently, greater stability when used for certain applications. Rheological additives, for example, viscosity index improvers, are one class of compounds produced by the saturation of diene polymers.
There is a continuing effor to develop improved hydrogenation catalysts and processes to selectively hydrogenate diene-containing polymers to hydrogenated polymeric products having desirable properties. The present invention is directed to a catalyst system and process for hydrogenating olefin polymers, especially diene-vinyl aromatic copolymers, to form polymers having reduced trans unsaturation and vinyl unsaturation, but with little change in aromatic unsaturation.